Questions
101
The settling velocity of a particle in a sedimentation tank increases if
Answer: None Of The Above
102
The detention period in coagulation tanks is usually kept as
Answer: 2 to 6 hours
103
The alum, when added as a coagulant in water
Answer: decreases pH value of water
104
In water treatment, rapid gravity filters are adopted to remove
Answer: bacteria and colloidal solids
105
The rate of filtration in slow sand filters in million litres per day per hectare is about
Answer: 50 to 60
106
Assertion A: Slow sand filters are more efficient in removal of bacteria than rapid sand filters.
Reason R : The sand used in slow sand filters is finer than that in rapid sand filters.
Select your answer based on the coding system given below:
Answer: Both A and R are true and R is the correct explanation of A
107
Air binding phenomena in rapid sand filters occur due to
Answer: excessive negative head
108
The percentage of filtered water, which is used for backwashing in rapid sand filters, is about
Answer: 2 to 4
109
The rate of Alteration of pressure filters is
Answer: greater than that of rapid sand filters
110
The process in which the chlorination is done beyond the break point is known as
Answer: Super Chlorination
111
The treatment of water with bleaching powder is known as
Answer: hypochlorination
112
The suitable method for disinfection of swimming pool water is
Answer: ultra violet rays treatment
113
Which of the following chemical compounds can be used for dechlorination of water ?
Answer: Sulphur Dioxide
114
In lime-soda process
Answer: lime reduces the carbonate hardness and soda-ash removes the non-carbo¬nate hardness
